added THROW and THROWIFNOT opcodes to engine

neo/VM/ExecutionEngine.py

@@ -752,6 +752,15 @@ def ExecuteOp(self, opcode, context):
 
                 estack.PushT(Struct(items))
 
+            elif opcode == THROW:
+                self._VMState |= VMState.FAULT
+                return
+
+            elif opcode == THROWIFNOT:
+                if estack.Pop().GetBoolean() == False:
+                    self._VMState |= VMState.FAULT
+                    return
+
             else:
 
                 self._VMState |= VMState.FAULT

neo/VM/OpCode.py

@@ -38,6 +38,11 @@
 TAILCALL = b'\x69'
 
 
+# Exceptions
+THROW = b'\xf0'
+THROWIFNOT = b'\xf1'
+
+
 #  Stack
 DUPFROMALTSTACK = b'\x6A'
 TOALTSTACK = b'\x6B' #  Puts the input onto the top of the alt stack. Removes it from the main stack.